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Experimental procedures and results of a benchmark test for springback are reported and a complete suite of obtained data is provided for the validation of forming and springback simulation software. The test is usually referred as the Slit-Ring test where a cylindrical cup is first formed by deep drawing and then a ring is cut from the mid-section of the cup. The opening of the ring upon slitting releases the residual stresses in the formed cup and provides a valuable set of easy-to-measure, easy-to-characterize springback data. The test represents a realistic deep draw stamping operation with stretching and bending deformation, and is highly repeatable in a laboratory environment. In this study, six different automotive materials are evaluated.

A typical forming operation of chassis components (control arms, cross members, etc.) often involves edge stretching and/or hole expansion. As a result, the edge split is a common forming failure mode. To overcome this problem, Japanese and European automakers use stretch flange high strength (SFHS) steel due to its high strength and excellent edge stretch capability. Recently, SFHS steel has gained greater attention in North America and is currently being used for upper and lower control arm applications. This paper includes a discussion on general edge stretch issues in forming operations, including material data that demonstrate the higher stretch limit of SFHS steel as compared to other high strength steels. In a case study, SFHS steel is applied to a control arm and finite element analysis (FEA) is conducted to evaluate forming and structural performance.

Tubular hydroforming is being used extensively for manufacturing various automotive structural parts due to its weight reduction and cost saving potentials. The use of a thin wall advanced high strength steel (AHSS) tube offers great potential to further expand hydroforming applications to upper body components. In this study, numerical and experimental investigations are conducted on a free expansion hydroforming case using various AHSS thin wall tubes. The results are also compared with tubes made from conventional steels and different tubing processes. The appropriate use of the forming limit in hydroforming is also discussed. In numerical study, a new simulation method is developed and validated to handle tube material properties input. Good correlations to the experimental data have been obtained. The new method only requires the flat sheet stress–strain curves as the basic material property. Tube and weld properties are modeled as a pre-strained tubular blank.